KR101569179B1 - Method of manufacturing eco-friendly ceramic protecting sleeve for sensor and composition used to the same - Google Patents

Abstract

The present invention relates to a composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor.
The composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor according to the present invention comprises 25 to 65% of an inorganic filler (wollastonite) in natural fiber, 15 to 55% of an inorganic filler in an artificial fiber (alkaline earth silicate fiber) 5 to 15% of a reinforcing material (glass fiber), 5 to 15% of an inorganic binder, and an organic binder.

Description

TECHNICAL FIELD [0001] The present invention relates to a composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor,

The present invention relates to a heat-resistant protective pipe for a sensor such as a thermocouple, a sampler and a composite probe, which is used for measuring the temperature of a molten metal, measuring a component and sampling a molten metal in a steelmaking or steelmaking process. More particularly, Here, a slurry obtained by mixing a synthetic inorganic fiber and a binder is formed on the outer surface of a mandrel or a paper tube made of a paper tube or a light metal, and is manufactured by a method of heat resistance, heat insulation, erosion resistance, non-splash in the molten metal, To a composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor.

Generally, the temperature of molten steel or molten steel is about 1300 ~ 1800 ℃. Therefore, when the thermocouple, the sampler and the composite probe are immersed in the molten metal for the measurement of the temperature of the molten steel or molten steel, the composition of the molten steel, and the sampling of the sample, the deterioration of the measuring portion due to the high temperature molten metal, It is necessary to use a heat-resistant protective pipe in order to secure the safety of the operator.

The heat-resistant protective tube is preferably made of a material excellent in heat resistance, thermal shock resistance, heat insulation, molten metal scattering prevention, and extrusion moldability in order to exhibit the inherent performance of the probe.

Conventionally, heat-resistant protective tubes are made of ceramic fiber, diatomaceous earth, wollastonite, etc. as main components.

Ceramic fiber is widely used because it is superior in heat resistance and heat insulation. However, when it is immersed in molten metal, silica is eluted at 1200 to 1400 ° C to contaminate the molten metal, and the erosion resistance is poor. Especially, the price of raw material is high, . Further, in the case of the ceramic fiber, harmful substances may be generated at the time of manufacturing the probe for molten metal and at the time of use, and it has been urgent to improve.

BACKGROUND ART [0002] A related art related to the present invention is a heat-resistant protective pipe for molten metal probes disclosed in Korean Patent Registration No. 10-0491986 (published on May 31, 2005), a method for manufacturing the same, and Korean Patent Registration No. 10-1129560 And a wollastonite heat protection pipe for a probe disclosed in the above publication.

 The diatomaceous earth and kaolin used as main materials in the above documents include crystalline silica such as Quartz and Cristobalite, and asbestos is contained in the seawall, which is known as a carcinogenic substance.

Furthermore, in the case of kaolin conventionally used as a heat-resistant material, large amounts of free silica (free SiO ₂ ), that is, a crystalline phase, cristobalite phase, are produced at 1000 ° C or higher. This is a cancer-causing substance that is internationally regulated and is unsuitable as an environment-friendly heat-resistant material.

Specifically, kaolin is heated to 925 ~ 950 ℃, and the water reacts and disappears and changes to meta kaolin as follows.

_{2Al 2 Si 2 O 5 (OH} ) 4 → 2Al 2 Si 2 O 7 + 4H 2 O

When this meta kaolin is heated above 1050 ° C, it turns into aluminum siliceous spinel and mullite as follows, and a large amount of free crystalline silica is formed.

This crystalline silica is harmful to the human body and thus can not be used as an environmentally friendly heat resistant material.

2Al ₂ Si ₂ O ₇ ? Si ₃ Al ₄ O ₁₂ + SiO ₂

Al ₄ O ₃ → 2Si ₁₂ 3Si ₂ Al ₆ O ₁₃ + 5SiO ₂

In addition, even if a small amount of slaked lime used in the past is used, it is difficult to produce due to the hydration phenomenon as a result of the hydration which reacts with water and becomes hard as a stone after a lapse of time. When it is stored by extrusion molding, Due to the volumetric expansion, the cracks are generated in the drying process and the defects are produced, so that it is difficult to stabilize the quality.

Also, the lime and quicklime are toxic. Therefore, these materials are not suitable as environmentally friendly heat resistant materials.

It is an object of the present invention to provide a composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor which is harmless to the human body.

In order to accomplish the above object, the composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor according to an embodiment of the present invention comprises 25 to 65% of a natural filler as an inorganic filler, 15 to 55% as an inorganic filler in an artificial fiber, Of an inorganic reinforcing material of 5 to 15%, an inorganic binder of 5 to 15% and an organic binder of 5 to 15%.

In order to accomplish the above object, according to another embodiment of the present invention, there is provided a composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor, which comprises 25 to 65% of a natural filler as an inorganic filler, 15 to 55% 5 to 15% of fibrous inorganic stiffener, 5 to 15% of inorganic binder, 5 to 15% of organic binder and 1 to 25% of artificial mineral refractory material.

In the above embodiments, the eco-friendly ceramic heat-resistant protective pipe for the sensor may further include not more than 5 wt% of the stake.

In addition, in the above embodiments, the inorganic filler in the natural fiber may include wollastonite, and the inorganic filler in the artificial fiber may include an alkaline earth silicate fiber. At this time, the wollastonite is preferably fibrous in aspect ratio of 15: 1 or more. The alkaline earth silicate fiber preferably has a particle diameter of more than 3 mu m and 10 mu m or less.

Further, in the another embodiment, the artificial mineral refractory material may include at least one of fused spinel and fused alumina. At this time, it is preferable that the fused spinel or the fused alumina is a powder of 80 to 120 meshes.

In addition, in the above embodiments, the inorganic reinforcing material on the artificial fiber may include a glass fiber. At this time, it is preferable that the diameter of the glass fiber is not less than 3 μm and not more than 10 μm, and the fiber length is 3 to 6 mm.

Also, in the above embodiments, the inorganic binder includes at least one of water glass, silica sol and alumina sol, and the organic binder is selected from the group consisting of Sodium of Carboxy Methyl Cellulose (CMC-Na), Polyvinyl Alcohol (PVA) Methyl cellulose) may be included.

The composition for the production of an eco-friendly ceramic heat-resistant protective tube for a sensor is characterized in that there is no structure of free crystalline silica and asbestos crystal phase.

The ceramic heat-resistant protective tube made of the composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor according to the present invention can protect the sensor part to perform sensor functions such as temperature, component measurement and sample collection even in a high temperature environment.

In particular, the composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor according to the present invention does not have a free crystalline silica or an asbestos crystal phase structure. Therefore, there is an advantage that it is harmless to the human body before and after use of the sensor.

In addition, the manufacturing method using the composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor according to the present invention is environmentally friendly because it minimizes the generation of dust during the process, and can reuse the scouring occurring during the process.

FIG. 1 schematically shows a method of manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor applicable to the present invention.
Figure 2 shows photographs of specimens prepared from compositions A through J after sediment deposition in an embodiment of the present invention.
Figure 3 shows the measured values of the sensors measured in the specimens made from composition G, H, I in an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

Hereinafter, a composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor according to the present invention will be described in detail with reference to the accompanying drawings.

Composition for manufacturing eco-friendly ceramic heat-resistant protective tube for sensor

The composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor according to the first embodiment of the present invention comprises 25 to 65% of inorganic filler in natural fiber form, 15 to 55% in inorganic filler in artificial fiber form, 5 to 15 in artificial fiber form, %, An inorganic binder in an amount of 5 to 15%, and an organic binder in an amount of 5 to 15%.

The eco-friendly ceramic heat-resistant protective pipe for the sensor may further include not more than 5 wt% of a stake.

Hereinafter, the role and content of each component included in the composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor according to the first embodiment of the present invention will be described.

Mineral filler in natural fiber form

The inorganic filler in the natural fiber is the main ingredient of the ceramic heat-resistant protective tube together with the inorganic filler in the artificial fiber. The inorganic filler in the natural fibrous form is typically wollastonite. The wollastonite is a natural fibrous mineral of calcium silicate, and its chemical formula is CaSiO ₃ , and it generally forms a fibrous or fine columnar crystal aggregate, but may form a radial or a bundle aggregate, Also.

The wollastonite used in the present invention has a rod-shaped needle-like structure, which increases the tensile strength and flexural strength, and does not significantly increase the viscosity even when the content is mixed with a polymer such as CMC. Wollastonite is low in hygroscopicity, has no crystal number, is excellent in dimensional stability, can be improved in reliability by complementing that the bending strength remarkably falls due to infiltration of moisture during the rainy season.

Furthermore, in the evaluation of carcinogenicity of the International Agency for Research on Cancer (IARC), it was classified as a safe natural fiber material belonging to 'Group 3' which is 'inability to classify human carcinogenicity' The risk is extremely low.

On the other hand, the wollastonite has an aspect ratio of 15: 1 or more.

The inorganic filler in the natural fiber is preferably contained in an amount of 25 to 65% by weight of the total weight of the composition. If the content of the inorganic filler in the natural fiber is less than 25% by weight, heat resistance and strength can not be maintained, so that the product may be melted at high temperatures or broken by cracks during use. On the other hand, when the content of the inorganic filler in the natural fiber is more than 65% by weight, the network structure peculiar to the needle-shaped material is excessively developed and the extrudability and the formability are drastically reduced due to the excessively developed structure.

Inorganic filler in artificial fiber form

The inorganic filler in the artificial fiber plays a role mainly in forming the mesh structure. As such an inorganic filler of an artificial fiber form, an alkaline earth silicate (AES) fiber can be typically presented. The alkaline earth silicate fiber is mainly composed of magnesia, alumina, silica, calcia and the like, and the fiber particles are preferably thick. Alkali earth silicate fibers which are harmless to human body are also distributed under the trade names of bio-cerak, super wool, amorphous fiber and large diameter, and are used as materials for forming a network structure as an artificial fibrous inorganic filler reinforcement.

The alkaline earth silicate fiber is advantageous in that the particle diameter is more than 3 탆 but not more than 10 탆. The alkaline earth silicate fiber of more than 10 탆 has difficulty in the manufacturing process, Extrusion may also be difficult. On the contrary, when the particle diameter of the alkaline earth silicate is 3 탆 or less, it is not preferable because it is easy to absorb in the body and can be deposited to the closed area.

The inorganic filler in the form of an artificial fiber is preferably contained in an amount of 15 to 55% by weight based on the total weight of the composition. If the content of the inorganic filler in the artificial fiber is less than 15% by weight, the structure of the network structure, which is a composite filler reinforcement material, is weakened and the tensile strength is lowered and the cohesiveness between materials is lowered. The problem may be solved. On the contrary, when the content of the inorganic filler in the artificial fiber is more than 55% by weight, the heat resistance is low, and when it is used in the molten molten metal, there is a problem that the burning occurs severely, and the cost is high.

Inorganic stiffener in artificial fiber form

The inorganic reinforcing material on the artificial fiber may be glass fiber.

Glass fiber is an E-glass type composite of SiO ₂ and Al ₂ O ₃ which can be amorphous and can act as a reinforcing material. The glass fiber preferably has a diameter of more than 3 탆 and 10 탆 or less and a fiber length of 3 to 6 mm. When the particle diameter of the glass fiber is 3 탆 or less, it is easy to inhale into the body, which is not environmentally friendly and can harm the human body. On the contrary, when the particle diameter of the glass fiber exceeds 10 mu m, the difficulty in the fiber manufacturing process is difficult and the production of the heat protection tube becomes very difficult. Also, when the fiber length of the glass fiber exceeds 6 mm, the manufacturing process may become difficult due to a problem that the glass fibers are entangled with each other. On the contrary, when the fiber length of the glass fiber is less than 3 mm, the dispersibility is good, but since it is difficult to form a link between the particles, microcracks may occur because the bonding force between the interfaces of the different raw materials is not reinforced.

The inorganic reinforcing material on the artificial fiber is preferably contained in an amount of 5 to 15% by weight of the total weight of the composition. If the content of the inorganic reinforcing material in the artificial fiber is more than 15% by weight, it is difficult to mix and extrude the raw materials due to being stuck to each other. In addition, there is a problem that glue fibers are caught in the extruder three- There is a difficulty in production. Moreover, such a problem may cause defects that cause cracks in the ceramic protection tube after use of the refuse. On the contrary, when the content of the inorganic reinforcing material in the artificial fiber is less than 5% by weight, the mesh structure in which the raw materials are entangled with each other is not formed, so that the characteristics of the composite material are weakened and deteriorated in the tile.

Binder

In the present invention, the binder is included for adhesion, and includes an inorganic binder and an organic binder.

The inorganic binder may include at least one of water glass, silica sol, and alumina sol.

The organic binder may be one or a mixture of two or more of CMC-Na (Sodium of Carboxy Methyl Cellulose), PVA (Polyvinyl Alcohol), MC (Methyl Cellulose) and PVA (Polyvinyl Alcohol). For example, CMC and MC can be used in powder form at room temperature and can be easily dissolved in water to improve the cohesion and flexibility of the particles, the extrudability due to viscosity increase, and the green strength.

Each of the inorganic binder and the organic binder is preferably contained in an amount of 5 to 15% by weight on a solid basis. If the content of the inorganic binder or the organic binder exceeds 15% by weight, it adheres to the wall of the impeller or the mixer, and the production capacity is deteriorated. Also, when the content of the inorganic binder or the organic binder exceeds 15% by weight, aggregation of particles due to van der Waals force increase may occur. The binder in fine particle form has excellent physico-chemical properties, but as the particle size decreases to nanosize, the pulling force between the particles (eg, silica sol) increases and the aggregation phenomenon occurs. Due to the hydroxyl group of CMC, . On the contrary, when the content of the inorganic binder or the organic binder is less than 5% by weight, the amount of the binder is too small to increase the filling density of the heat protection tube, and a large amount of bubbles are formed on the surface of the molding sleeve, The strength is lowered, affecting the quality.

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Paper powder is an organic additive, which is larger in volume than wollastonite, for example, and thus has a lower density to improve its dispersibility, thereby effectively reducing the weight and making it less susceptible to external impacts.

When a stake is contained, the content thereof is preferably 5% by weight or less on a solid basis. When the content of the staple exceeds 5 wt%, there is a fear of component contamination at the time of sampling of the sensor, and since it is difficult to be stored for a long time due to corruption, the whiteness of the appearance of the heat protection tube decreases It is not good for cosmetics.

The eco-friendly ceramic heat-resistant protective tube for a sensor manufactured as described above has a density of 2.2 to 2.5 g / cm 3 and is relatively light in weight, and can be appropriately used for the characteristics of a heat-resistant protective pipe used for immersion in molten metal for several seconds.

The composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor according to the second embodiment of the present invention comprises 25 to 65% of inorganic filler in natural fiber form, 15 to 55% in inorganic filler in artificial fiber form, %, An inorganic binder of 5 to 15%, an organic binder of 5 to 15%, and a synthetic inorganic refractory material of 1 to 25%.

The composition for manufacturing an eco-friendly ceramic heat-resistant protective tube according to the second embodiment is the same as the composition of the eco-friendly ceramic refractory material according to the first embodiment except for the addition of the artificial mineral refractory material. Only the role and content will be described.

Artificial mineral refractory

The ceramic heat-resistant protective tube manufactured from the composition for manufacturing an eco-friendly ceramic heat-resistant protective tube according to the first embodiment as described above has an advantage of being relatively light in weight. However, a higher level of heat resistance may be required in a measurement environment having a large flow depending on a process or a very high temperature, and thus, a refractory material of artificial mineral may be added to increase the melting point of the heat resistant material.

Such an artificial mineral refractory material may include at least one of fused spinel and fused alumina. At this time, it is preferable that the fused spinel or the fused alumina is a powder of 80 to 120 meshes (170 to 74 mu m). Fused spinel or fused alumina with such a condition does not contain free crystalline silica (Cristalline Silica) which is harmful to the human body, so that it is not harmful to the human body and the working environment can be improved without dust.

The artificial mineral refractory material is preferably contained in an amount of 1 to 25% by weight based on the total weight of the composition. If the content of the artificial mineral refractory material is less than 1% by weight, the effect of the addition is insufficient. On the contrary, when the content of the artificial mineral refractory material exceeds 25% by weight, the weight of the ceramic heat-resistant protective pipe may be excessively increased, and the mesh structure of the heat-resistant protective pipe may not be densified.

The composition for manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor according to the first and second embodiments is characterized in that there is no structure of free crystalline silica and asbestos crystal phase.

For this purpose, wollastonite, which is an inorganic filler in natural fiber form, can be used in an amount of 100mesh or more and can contain a product containing 45% by weight or more of CaO and 47% by weight or more of SiO ₂ , and the content of alumina may be high. In addition, the man-made fibrous inorganic filler alkaline earth silicate fibers are long fibers and the temperature as a bulk average diameter 5㎛ over more than 1280 ℃, CaO and MgO 18 ~ 43% by weight, SiO ₂ 50 ~ 82% by weight, Al ₂ 2% by weight of O _{3, and} 2% by weight of TiO ₂ can be used. In addition, the glass fibers can be cut into 3 to 6 mm and products having an average diameter of 5 μm or more can be used. In addition, the molten spinel is a reverse spinel product having a weight ratio of magnesium and aluminum of 2: 8. The purity is at least 99%, and the product of 80 to 100mesh can be used in a ratio of 0.2mm or less.

Manufacturing method of eco-friendly ceramic heat-resistant protective pipe for sensor

FIG. 1 schematically shows a method of manufacturing an eco-friendly ceramic heat-resistant protective tube for a sensor applicable to the present invention.

Referring to FIG. 1, the method for manufacturing an eco-friendly ceramic heat-resistant protective pipe for a sensor includes a composition manufacturing step (S110), an extrusion molding step (S120), a cutting step (S130), and a drying step (S140).

First, in the composition preparing step (S110), a raw material is added to a stirrer or a mixer to prepare the composition according to the first or second embodiment.

The inorganic filler reinforcing materials such as glass fiber and alkaline earth silicate fibers are weighed and placed in a stirrer. Diluted silica sol or diluted water glass, which is an inorganic binder, is added and mixed for about 15 minutes. Spinel and wollastonite (In this case, it is preferable to carry out the metering in the order of the added amount), adding CMC which is an organic binder, adding silica sol or water glass as an inorganic binder, stirring for about 30 minutes to 60 minutes have.

If necessary, further aging the prepared composition. Aging can be carried out by sealing the prepared composition with vinyl and aging for a day or so.

Next, in the extrusion molding step (S120), the composition is put into an extruder and extruded in the form of a sleeve.

For extrusion molding in the form of a sleeve, an extrusion core rod is provided in the extruder. At this time, the ceramic heat-resistant protective pipe manufactured by using the branch pipe as the extruded mandrel can have the integral structure of the branch pipe.

Next, in the cutting step (S130), both ends of the extrusion-molded product are cut so that a ceramic heat-resistant protective tube having a predetermined size can be produced.

Further, before the cutting, the extrudate can be dried in the drying drum for about 20 minutes or completely dried.

On the other hand, the squid removed in the cutting step can be reintroduced into the agitator or the mixer to improve the productivity.

Next, in the drying step (S140), the cut product is dried.

More specifically, the drying includes a natural drying process and a drying and curing process. During the natural drying process, the crops are dried naturally for 4 to 12 hours. In the dry curing process, the naturally dried product is firstly heated to 50 to 70 ° C for 20 to 40 minutes, then maintained for 20 to 40 minutes for the first time, raised to 120 to 150 ° C for 20 to 40 minutes, After the second maintenance for the minute, it naturally cools.

Most of the ceramic materials are completed through a baking step, whereas the eco-friendly ceramic heat-resistant protective tube for a sensor according to the present invention is characterized by being made of fluorine which is completed only by a drying step without a firing process. As a result, it is possible to obtain the effect of shortening the manufacturing cost and manufacturing time.

Example

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

1. Preparation of specimens

The composition having the composition shown in Table 1 was prepared, extruded from the extruder, dried for 20 minutes, cut at both ends, naturally dried for 8 hours, heated for 30 minutes at 60 DEG C for 30 minutes Kept for 1 hour, warmed up to 130 캜 for 30 minutes, maintained for 120 minutes, and then naturally cooled.

In Table 1, silica sol was used with water at a ratio of 10: 1 by weight.

[Table 1]

Specimen A shows, as a comparative example, that an inorganic reinforcing material in the form of an artificial fiber is not included. Specimen B shows that, as a comparative example, less than 5% by weight of an inorganic reinforcing material in the form of an artificial fiber. Sample D shows, as a comparative example, less than 15% by weight of an inorganic filler in the form of an artificial fiber.

The chemical composition of the final composition for manufacturing a heat-resistant protective tube is shown in Table 2.

2. Property evaluation method and result

(1) The diameter burning rate after the dipping step shows the amount of change in diameter before and after use, and it can be judged that the test sample with a large burning rate is heat-resistant and impact-resistant.

(2) The expected melting temperature shows the theoretical melting point according to the chemical composition. If the melting point is too low, it can not be used as a ceramic heat-resistant protective tube for sensors.

(3) "Splashability" means that splashes are scattered as much as possible when dipped in dirt, and that no dust is generated during the production process of the product, smooth extrusion molding is possible, And the like.

(4) The impact resistance test was carried out by observing the bending strength of 230 Kgf or more of the heat resistant protective pipe integrated with the core tube, the stapling operation (applied at 6 bar), and the damage by the automatic transfer device CAM. The heat resistance and thermal shock resistance were 10 After superdeposition, it was tested by judging whether it was broken, cracked or melted.

The evaluation results of the physical properties are shown in Table 2. Further, photographs of the specimens prepared from the compositions A to J after sedimentation are shown in FIG.

[Table 2]

Referring to Table 2 and FIG. 2, it can be seen that the specimens of the other embodiments showed excellent results as compared with the specimens A, B and D of the comparative examples, and that the specimens G, H, have. In case of specimen E, the physical properties were good, but it was evaluated as △ because the inorganic filler on the artificial fiber was expensive.

Figure 3 shows the measured values of the sensors measured in the specimens made from composition G, H, I in an embodiment of the present invention.

Referring to FIG. 3, in the case of the samples prepared from the compositions G, H and I, no significant influence was exerted on the measurement environment, and a result that can be normally measured was obtained.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Such changes and modifications are intended to fall within the scope of the present invention unless they depart from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

Claims (11)

By weight of an inorganic filler, 25 to 65% of a natural filler, 15 to 55% of an inorganic filler in an artificial fiber, 5 to 15% of an inorganic filler in an artificial fiber, 5 to 15% of an inorganic binder and 5 to 15% Wherein the heat-resistant protective tube is made of a thermoplastic resin.
Wherein the inorganic filler is in the range of 25 to 65% by weight, the inorganic filler in the natural fiber is 15 to 55%, the inorganic filler in the artificial fiber is 15 to 55%, the inorganic filler in the artificial fiber is in the range of 5 to 15%, the inorganic binder is 5 to 15% Wherein the refractory material comprises 1 to 25% of a refractory material.
3. The method according to claim 1 or 2,
The eco-friendly ceramic heat-resistant protective tube for the sensor
By weight based on the total weight of the composition.
3. The method according to claim 1 or 2,
Wherein the natural fibrous inorganic filler comprises wollastonite,
Wherein the inorganic filler in the form of an artificial fiber comprises an alkaline earth silicate fiber.
5. The method of claim 4,
Wherein the wollastonite is fibrous in aspect ratio of 15: 1 or more.
5. The method of claim 4,
Wherein the alkaline earth silicate fiber has a particle diameter of more than 3 mu m to 10 mu m or less.
3. The method of claim 2,
Wherein the artificial mineral refractory material comprises at least one of fused spinel and fused alumina.
8. The method of claim 7,
Wherein the fused spinel or fused alumina is a powder of 80 to 120 meshes.
3. The method according to claim 1 or 2,
Wherein the inorganic stiffener on the artificial fiber comprises a glass fiber.
10. The method of claim 9,
Wherein the glass fiber has a diameter of more than 3 占 퐉 and 10 占 퐉 or less and a fiber length of 3 to 6 mm.
3. The method according to claim 1 or 2,
Wherein the inorganic binder includes at least one of water glass, silica sol and alumina sol,
Wherein the organic binder comprises at least one of CMC-Na (Sodium of Carboxy Methyl Cellulose), PVA (Polyvinyl Alcohol), and MC (Methyl Cellulose).

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